// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_GPU_VAAPI_JPEG_DECODE_ACCELERATOR_H_
#define MEDIA_GPU_VAAPI_JPEG_DECODE_ACCELERATOR_H_

#include <stdint.h>

#include <memory>

#include "base/macros.h"
#include "base/memory/linked_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/lock.h"
#include "base/threading/non_thread_safe.h"
#include "base/threading/thread.h"
#include "media/base/bitstream_buffer.h"
#include "media/gpu/media_gpu_export.h"
#include "media/gpu/shared_memory_region.h"
#include "media/gpu/vaapi_jpeg_decoder.h"
#include "media/gpu/vaapi_wrapper.h"
#include "media/video/jpeg_decode_accelerator.h"

namespace media {

// Class to provide JPEG decode acceleration for Intel systems with hardware
// support for it, and on which libva is available.
// Decoding tasks are performed in a separate decoding thread.
//
// Threading/life-cycle: this object is created & destroyed on the GPU
// ChildThread.  A few methods on it are called on the decoder thread which is
// stopped during |this->Destroy()|, so any tasks posted to the decoder thread
// can assume |*this| is still alive.  See |weak_this_| below for more details.
class MEDIA_GPU_EXPORT VaapiJpegDecodeAccelerator
    : public JpegDecodeAccelerator {
public:
    VaapiJpegDecodeAccelerator(
        const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
    ~VaapiJpegDecodeAccelerator() override;

    // JpegDecodeAccelerator implementation.
    bool Initialize(JpegDecodeAccelerator::Client* client) override;
    void Decode(const BitstreamBuffer& bitstream_buffer,
        const scoped_refptr<VideoFrame>& video_frame) override;
    bool IsSupported() override;

private:
    // An input buffer and the corresponding output video frame awaiting
    // consumption, provided by the client.
    struct DecodeRequest {
        DecodeRequest(int32_t bitstream_buffer_id,
            std::unique_ptr<SharedMemoryRegion> shm,
            const scoped_refptr<VideoFrame>& video_frame);
        ~DecodeRequest();

        int32_t bitstream_buffer_id;
        std::unique_ptr<SharedMemoryRegion> shm;
        scoped_refptr<VideoFrame> video_frame;
    };

    // Notifies the client that an error has occurred and decoding cannot
    // continue.
    void NotifyError(int32_t bitstream_buffer_id, Error error);
    void NotifyErrorFromDecoderThread(int32_t bitstream_buffer_id, Error error);
    void VideoFrameReady(int32_t bitstream_buffer_id);

    // Processes one decode |request|.
    void DecodeTask(const std::unique_ptr<DecodeRequest>& request);

    // Puts contents of |va_surface| into given |video_frame|, releases the
    // surface and passes the |input_buffer_id| of the resulting picture to
    // client for output.
    bool OutputPicture(VASurfaceID va_surface_id,
        int32_t input_buffer_id,
        const scoped_refptr<VideoFrame>& video_frame);

    // ChildThread's task runner.
    scoped_refptr<base::SingleThreadTaskRunner> task_runner_;

    // GPU IO task runner.
    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;

    // The client of this class.
    Client* client_;

    // WeakPtr<> pointing to |this| for use in posting tasks from the decoder
    // thread back to the ChildThread.  Because the decoder thread is a member of
    // this class, any task running on the decoder thread is guaranteed that this
    // object is still alive.  As a result, tasks posted from ChildThread to
    // decoder thread should use base::Unretained(this), and tasks posted from the
    // decoder thread to the ChildThread should use |weak_this_|.
    base::WeakPtr<VaapiJpegDecodeAccelerator> weak_this_;

    scoped_refptr<VaapiWrapper> vaapi_wrapper_;

    // Comes after vaapi_wrapper_ to ensure its destructor is executed before
    // |vaapi_wrapper_| is destroyed.
    std::unique_ptr<VaapiJpegDecoder> decoder_;
    base::Thread decoder_thread_;
    // Use this to post tasks to |decoder_thread_| instead of
    // |decoder_thread_.task_runner()| because the latter will be NULL once
    // |decoder_thread_.Stop()| returns.
    scoped_refptr<base::SingleThreadTaskRunner> decoder_task_runner_;

    // The current VA surface for decoding.
    VASurfaceID va_surface_id_;
    // The coded size associated with |va_surface_id_|.
    gfx::Size coded_size_;
    // The VA RT format associated with |va_surface_id_|.
    unsigned int va_rt_format_;

    // The WeakPtrFactory for |weak_this_|.
    base::WeakPtrFactory<VaapiJpegDecodeAccelerator> weak_this_factory_;

    DISALLOW_COPY_AND_ASSIGN(VaapiJpegDecodeAccelerator);
};

} // namespace media

#endif // MEDIA_GPU_VAAPI_JPEG_DECODE_ACCELERATOR_H_
